1. Field of Invention
The present invention relates to a stress-indicating rope-tightening apparatus.
2. Related Prior Art
A rope-tightening device is used to tighten a rope for bundling an object or more. However, the rope would be broken if the stress therein exceeds a limit. In the case of the rupture of the rope, loss of property is inevitable. What is worse, casualty might be entailed.
To avoid the foregoing drawbacks, a conventional rope-tightening device 1 is equipped with a stress-indicating unit as disclosed in Taiwanese Patent M279629. The rope-tightening device 1 includes a frame 10, a first hook 11 attached to the frame 10, a second hook 15, a pulley connected to the second hook 15, a rope 14 wound around the pulley, a reel 13 disposed on the frame 10 for reeling the cable 14 and a handle 12 disposed on the frame 10 for rotating the reel 13. The reel 13 includes two ratchet wheels. Two detents 121 are connected to the handle 12. When the handle 12 is pivoted relative to the reel 13 in a direction, the detents 121 engage with the ratchet wheels so that the handle 12 rotates the reel 13 to tighten the rope 14. When the handle 12 is pivoted relative to the reel 13 in an opposite direction, the detents 121 rattle on the ratchet wheels so that the handle 12 does not rotate the reel 13 to slacken the rope 14.
The stress-indicating unit includes a strain gauge 101, an integration element 102 and a display 103. The strain gauge 101 is disposed on a side of the frame 10. The strain gauge 101 and the display 103 are electrically connected to the integration element 102. The use of the stress-indicating unit is based on an assumption that the stress in the frame 10 gets larger as the stress in the rope 14 gets larger. The strain gauge 101 detects the strain in the frame 10. The integration element 102 calculates the stress in the rope 14 based on the strain in the frame 10. The integration element 102 instructs the display 103 to show the stress in the rope 14. However, the operation is not precise as the strain gauge 101 is disposed on the frame 10. The monitoring of the stress is inconvenient as the display 103 is disposed on the side of the frame 10.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in the prior art.